Summary: Sexual conflict promotes speciation in insects
Goš ran Arnqvist*, Martin Edvardsson, Urban Friberg, and Tina Nilsson
Department of Ecology and Environmental Science, Animal Ecology, University of Umeć, SE-901 87 Umeć, Sweden
Communicated by Richard D. Alexander, University of Michigan, Ann Arbor, MI, June 15, 2000 (received for review January 16, 2000)
Speciation rates among extant lineages of organisms vary exten-
sively, but our understanding of the causes of this variation and,
therefore, the processes of speciation is still remarkably incom-
plete. Both theoretical and empirical studies have indicated that
sexual selection is important in speciation, but earlier discussions
have focused almost exclusively on the potential role of female
mate choice. Recent findings of postmating reproductive conflicts
of interest between the sexes suggest a quite different route to
speciation. Such conflicts may lead to perpetual antagonistic co-
evolution between males and females and may thus generate
rapid evolutionary divergence of traits involved in reproduction.
Here, we assess this hypothesis by contrasting pairs of related
groups of insect species differing in the opportunity for postmat-
ing sexual conflict. Groups where females mate with many males
exhibited speciation rates four times as high as in related groups
where females mate only once. Our results not only highlight the